Numerous mechanisms are known in the prior art for use in connection with the reeling and unreeling of cords and wires of various types. These various known mechanisms, which are utilized both in connection with electrical equipment and mechanical devices, also may include various locking devices, which are intended to prevent the unintentional rewinding of the reel under various conditions and in various environments.
The most common mechanical types of reeling and unreeling mechanisms which can be "locked" into position to prevent rewinding except when desired are of the type commonly used in households for lowering blinds and curtains. These generally require that the cord be pulled in a desired direction in order to activate and deactivate such mechanical locking mechanisms.
The state of the art with respect to these various locking mechanisms is represented, for example, by U.S. Pat. No. 875,280 to McGavin. This patent thus includes a typical arrangement which employs a lever 12 and a screw 13 to engage a ratchet wheel so that upon pulling of a cord the lever is moved to withdraw the screw from the ratchet's teeth and permit rewinding under the force of spring 9. In connection with lighting fixtures in general, such devices are shown in patents such as U.S. Pat. No. 1,559,092 to Hallberg and U.S. Pat. No. 488,298 to Welsh.
The application of such devices to the winding and unwinding of electrical cords is represented, for example, by U.S. Pat. No. 4,114,273 to McGaha. This patent relates generally to dental equipment, and includes a mechanism for reeling and unreeling various dental instruments. The apparatus disclosed in this patent, as shown in FIGS. 6 and 7 thereof, utilizes an electrically actuated magnetic coil 50 which, when actuated, magnetically attracts pawls 46 moving into and out of engagement with a ratchet wheel 45. The magnetic coil 50 is electrically actuated, and a rather sophisticated arrangement, employing an electric eye, is shown for controlling same. This patentee also discusses the use of a switch 58 to manually operate the entire circuit.
In connection with various drop lights, particular problems have been encountered, none of which are overcome by these mechanisms which are known in the art. For example, in addition to being involved with electrical equipment, namely a light, drop lights generally employ extremely long conductors. This is normally the case because of the fact that the reeling and unreeling mechanism employed may be located long distances from the location where the light is intended to be used, such as being attached to high ceilings, etc. In addition, the light itself must be used in a confined area, and must be readily accessible and controllable. The devices employed in the past in connection with such an apparatus are generally of the conventional types discussed above, including the normal locking mechanisms which require one to pull on the conductor itself in order to release mechanical lock means and permit rewinding under the action of the spring loaded reel. In view of the length of the conductors generally utilized in this area, the dangers associated with this device have been considerable. For example, unintended release of the locking mechanism, such as by inadvertent movement of the wire, individuals tripping over the long conductors, etc., can result in the drop lights inadvertently rewinding, with concomitant potential damage to equipment, injuries to personnel, etc.